Breathless numbers

In this series of articles we will look at the Technology of the F1 car. Peeling away the layers to see what makes these cars the pinnacle of Motorsport. F1 has been going since 1946, based around a set of rules (the Formula) that are constantly changed to manage; speed, safety, improve overtaking, cut costs or improve the cars environmental efficiency. Overriding all the detailed rules, is the demand that F1 cars must single seaters, with open cockpits and the wheels uncovered.

The statistics around an F1 car are incredible, they weight just 640kg (including the driver) and currently have upto 830hp (with KERS), this makes their power to weight ratio greater than nearly any other car. If you compare an F1 car to a Bugatti Veyron, which has nearly 1000hp but weighs nearer two tones, has a ratio more than half that of the F1 car. Only dragsters have a greater power to weight ratio, but then they don’t go around corners anywhere near as fast as an F1 car! All this performance comes from a tiny 2.4 litre V8 engine and a tiny gearbox with seven gears. To allow the car to be so light and still strong enough, most of its structure is made from Carbon fibre, with precious metals such as titanium being used for highly stressed parts. Although humble steel and aluminium are still used in some of the mechanical parts of the car.

Equally an F1 car can accelerate 0-100kph in 2.5 and go on to a top speed of over 300kph. One lightly modified F1 car went on to achieve a top speed of 400kph!

When it comes to corners F1 cars have no rivals, with loads of 5g under braking and over 3g in corners. This amazing cornering performance comes from the cars grippy tyres and immense downforce. Downforce is the aerodynamic load the wings and bodywork create to literally suck the car onto the ground. Approaching 200kph an F1 car is creating its own weight in downforce, it’s often suggested that its possible for an F1 car to drive upside down on the roof of a tunnel at high speed, such is the force exerted by the wings onto the car.

We can start to break down the F1 car by looking at its major components visible from the outside. Although most of the complexity lies beneath the streamlined carbon fibre bodywork.

Dominating the look of the car from the front, the front wing is a critical part of the cars aerodynamics. It creates nearly 25% of the cars downforce. Under the current rules the wing is a massive 1.8m wide, although the teams have to use a mandatory 50cm middle section based on an FIA template. Each side of this centre section are the left and right wing spans. They can be made up from two of three aerofoil sections, known as flaps. Shaped like an inverted aircraft wing, faster moving air below the wing creates low pressure and sucks the car to the track. To keep the high pressure above separated from the lower pressure created beneath, teams fit an endplate to the wing to help seal it. These endplates, along with the curvature of the wingspans are becoming ever more complex and twisted as the teams use the flow trailing from the wing improve the airflow further down the car.

Acting as the partner to the front wing, the rear wing also creates some 25% of the cars downforce. Rules have increasingly reduced the size and effectiveness of the rear wing to cap cornering speeds. Currently the rear wing is just 75cm wide and can only have two aerofoil sections. Sitting high up in the airflow the rear wing also creates aerodynamic drag. This slows the car as high speed as the car has to pull the wing through the air. Now the rules allow the team to flatten the rearmost flap on the rear when following another car. This is known as DRS (drag reduction system), it boosts top speed to help the driver to pass the car in front during the race.

Hidden at the rear of the car, what appears to be a big black hole under the car is in fact the most important aerodynamic device, the Diffuser. This ramped section between the rear tyres also creates low pressure in a similar way to a wing, but is much more efficient. The diffuser creates nearly 50% of the cars downforce. Being so powerful the rules have progressively been tightened, making the diffuser smaller and smaller to cap cornering speeds. The diffuser is now just 1m wide and 12.5cm tall. In recent seasons teams have found way to increase the performance of the diffuser, such as the double decker diffuser introduced in 2009 and banned for 2011. Then the teams found blowing the exhaust gasses over the diffuser also increased its performance. This was introduced in 2010 and is banned for 2012.

The large bodywork panels either side of the car are called the sidepods. These house the water and oil radiators to cool the engine. They also house a lot of the electronics, battery and coolers for the gearbox. Just as with the rear wing, these sit out in the airflow and slow the car down. Teams strive to make the sidepods as small as possible while still being able to cool the engine. In 2011 we saw several team try different approaches to the sidepods shape: McLaren having a “U” shaped pair of sidepods, Red Bull having tiny sidepods and Toro Rosso lifting their sidepods up clear of the floor. Shaping the sidepods will reduce drag and improve flow over the top of the diffuser, making the car faster in turns.

One of the factors that has made F1 so safe in recent years has been the development of the survival cell, often also termed the monocoque. This carbon fibre structure forms the cockpit and the 150l fuel tank. Its incredibly strong and features panels along the side to prevent parts penetrating the survival cell during an accident and injuring the driver. So robust are these cells that teams will often only build four of five during a season.

Sitting above the front wing and aiding the survival cell for crash safety is the nose cone. This can be quickly bolted to the front of the survival cell, to allow mechanics access and to replace a damaged front wing. The nose cone has grown to be so long in order to meet the FIA crash tests. Along with the survival cell the nose cone will undergo several crash tests to ensure the car will safely survive an accident with out injuring the driver.

An F1 cars Pirelli tyres are the critical link in getting all the engine power, braking and cornering forces from the car back into the track, Thus to maximise grip the tyres are slick, without any tread. If conditions should lead to rain then the teams have access to two types of grooved tyre for light or heavy rain. Rules demand the wheels are just 33cm diameter, in contrast the road car fashion for ever large wheels and lower tyre sidewalls. The bulbous tyres also form part of the cars suspension, a lot of the cars vertical movement over bumps in the track is taken up from the tyre squashing, rather than the suspension moving.

Outwardly the suspension on an F1 car is very simple. At each corner of the car two “V” shaped arms, known as wishbones, attach the wheel to the chassis. Then another arm operates the spring and shock absorber, these are mounted inside the car to keep them out of the airflow for better aerodynamics. However it’s the detail work in the angle of these arms and the complex mechanical parts inside the car that make the suspension work so well. Teams use the suspension to improve the cars low speed grip and to keep the car at the right angle to the track to allow the aerodynamics to work best. Unfortunately for the driver his comfort is a low priority when the team set the suspension up.